Ultrasonic waves are used in various cleaning applications, in medical diagnostic and therapeutic applications, and for a number of research and investigative purposes. Ultrasound has become a widely used, medical diagnostic tool and is generally considered to be safe as well as non-invasive. One of the more well known medical applications is in the creation of visual images of fetuses in the human womb for diagnostic purposes. In other medical areas, however, ultrasound is now used as a diagnostic tool in the creation of visual images of muscles, tendons, and various internal organs. In such applications, the size, structure, and pathological lesions of bodily soft tissues can be captured via real time tomographic images.
Compared with other diagnostic technologies, such as magnetic resonance imaging (MRI) and computed tomography (CT), ultrasound machines are relatively inexpensive and portable. While X-rays are useful for medical purposes in obtaining images of bones, ultrasonic waves find their medical applications in the creation of soft tissue images. An advantage of ultrasonic waves is that they do not have the negative biological effects associated with X-rays or with other techniques involving radioactive materials.